Low-Level Radiation Waste Management System

This invention relates to the collection, containment and disposal of low-level radiation waste materials.

Hospitals, scientific laboratories and other similar facilities require the capability of collecting, containing and disposing of low-level radiation waste materials. In a hospital, for instance, the materials may comprise bandages, dressings, patient drapes, tubing or equipment, etc. which become contaminated during radiation treatments.

Such low-level radiation wastes are presently managed by placing a lead-lined metal container in the treatment area. The lead-lined metal container is open-topped and includes a lead-lined lid member providing closure; the system is basically a lead-lined barrel with a lid. Upon being filled, the entire barrel and lid structure must be removed as a unit, including wastes, and a new one placed at the collection site. The rigid metal drum and its lead lining comprise a container which is heavy and bulky and which cannot be moved by hand. Accordingly, it is necessary to utilize machinery such as cart or small forklift to remove a filled container and place a new container. This adds considerable expense, complexity and inconvenience of collection low-level radiation waste.

Similar considerations carry over to disposal of the low-level radiation wastes collected in metal/lead drums. Generally, the drums are trucked to a storage site and are buried. The aforementioned problems of handling a heavy, bulky drum continue in the disposal phase and, further, the final result is the disposal of a relatively expensive drum structure together with the low-level radiation waste.

It is a principal object of the invention herein to provide an improved way of collecting, containing and disposing of low-level radiation waste materials.

It is an additional object of the invention herein to provide an efficient, low-cost way of collecting, containing and disposing of low-level radiation waste material.

It is a further object of the invention herein to provide a low-level radiation waste management system for collecting, containing, transporting and disposing of the radioactive waste materials.

It is yet another object of the invention to provide a low-level radiation waste management system which is inexpensive to manufacture and causes minimum intrusion upon and disruption of activities at the collection/containment site.

A low-level radiation waste management system according to the invention herein comprises a container set including a liner having a closed end and an open end, and being adapted for deployment in a rigid open-topped receptacle for receiving low-level radiation waste. The receptacle liner includes a tie-receiving closure portion adjacent the open end, said closure portion being evertable to lie on the exterior of the open-topped receptacle. A cover is adapted to fit over the open-topped receptacle and the receptacle liner therein, the cover including a skirt portion to assure overlapping relationship.

The receptacle liner and cover are fabricated of a material, preferably a vinyl-encapsulated lead material, which absorbs radiation and prevents the passage of radiation from within the receptacle.

When it is desired to remove the accumulated low-level radiation waste, the cover may be dropped into the receptacle liner, continuing to provide a shield from the waste. Although the underside of the cover and the interior of the receptacle liner become contaminated by radiation emanating from the collected low-level radiation waste, the everted liner portion remains uncontaminated and may be uneverted, gathered and tied to close the receptacle liner. It will be appreciated that the portion of the receptacle liner extending above the tie is uncontaminated and presents no health hazard. The tied receptacle liner provides a relatively lightweight and easily handled package for transport to a disposal site, where it may be buried. The receptacle liner may be used with a fiberboard barrel or other receptacle, which may be maintained at the collection site and reused with subsequently installed receptacle liners and covers.

In a preferred embodiment, the receptacle liner and cover are fabricated of a three-layer material including two layers of a vinyl film sandwiching the vinyl-encapsulated lead sheet, and the seams are dielectrically welded to provide an air-tight and water-tight seal.

Other and more specific features and objects of the invention herein will in part be apparent to those skilled in the art and will in part also appear from the following description of the preferred embodiment and the claims taken together with the drawings.

FIG. 1 is a perspective view of a low-level radiation waste management system according to the invention herein;

FIG. 2 is a perspective view of the low-level radiation waste management system of FIG. 1, shown containing collected waste and closed for transport and disposal;

FIG. 3 is a sectional view, partially cut away, of the low-level radiation waste management system of FIG. 1; and

FIG. 4 is an enlarged fragmentary sectional view of a seam portion of the low-level radiation waste management system of FIG. 1.

The same reference numerals refer to the same elements throughout the various Figures.

A low-level radiation waste management system according to the invention herein generally comprises a receptacle having an open-top and a container set including a receptacle liner received in the receptacle and a cover removably received over the open top of the receptacle.

With reference to FIGS. 1-3, a preferred embodiment 10 of a low-level radiation waste management system according to the invention herein is illustrated. FIG. 4 shows details of its structure. The low-level radiation waste management system 10 generally comprises a receptacle 15 and a container set 20, the container set 20 including a receptacle liner 25 and a cover 30.

The receptacle 15, which is perhaps best seen in FIG. 2, is an open-topped barrel including a cylindrical sidewall 32 and a bottom 34 (FIG. 3). The upper edge 36 of the cylindrical sidewall 32 defines the open top of the receptacle 15. As more fully discussed below, the receptacle 15 supports the container set 20 in operative position, but the receptacle 15 itself does not need to provide any radiation shielding function. Accordingly, the receptacle 15 is fabricated of sturdy fiberboard, although fiberglass or metal containers are suitable as well.

The receptacle 15 is placed at the desired location for collecting low-level radiation wastes, and does not have to be moved from that location in order to dispose of the waste. The receptacle 15 is also preferably marked with the radiation warning symbol, as indicated at 38.

The container set 20 includes the receptacle liner 25 and cover 30. The material from which the container set 20 is fabricated is best seen in FIG. 4, which is an enlarged sectional view of a portion of the cover 30. The material, which is given the general number 40 in FIG. 4, comprises a central layer 42 of vinyl-encapsulated lead which is an effective block of the radiation emanating from low-level radiation wastes. The material 40 further comprises first and second vinyl (PVC) sheets 44 and 46 flanking the central vinyl-encapsulated lead sheet 42. The vinyl sheets 44 and 46 separate the central layer from user contact, thereby preventing the user from contacting and absorbing lead from the central layer.

The vinyl sheets 44, 46 and also contribute to the strength, liquid, integrity, and seam sealing properties of the material 40. A seam 50 between two adjacent panels of the material 40 is best illustrated in FIG. 4. The seam 50 is preferably formed by dielectric welding, which fuses the six total layers of the two panels together. Of particular importance from a sealing standpoint is that the inside layers 44 and 44a of the adjacent panels fuse and form a liquid tight seal, almost akin to a bead, at 52. Overlapping seams are also used as appropriate, and edges are fused as at 48, or may be stitched (not shown). It will be appreciated that the vinyl sheets 44, 46 may be bonded or coated to the outer surfaces of the vinyl-encapsulated lead 42, or may be merely a coating thereon.

The receptacle liner 25 is fabricated of two panels of the material 40, having side seam 54 best seen in FIG. 1, and side seam 56 and bottom seam 58, the latter two seams being best seen in FIG. 3. The side seams 54, 46 are preferably overlapped, dielectrically welded seams, and the bottom seam 58 is inturned and dielectrically welded. The top of the receptacle liner 25 is left open and the upper edge 49 is fused or stitched to join the three layers of material.

The receptacle liner 25 is inserted into the receptacle 15 and is of sufficient length to provide an upper tie-receiving closure portion 60 which is everted to lie on the exterior of the receptacle 15 during the on-site collection and containment functions, per FIGS. 1 and 3. The cover 30 comprises a top panel 62 sized and shaped to fit over the open top of the receptacle 15, including the everted tie-receiving closure portion 60 thereof, and a depending skirt 64 extending along the everted tie-receiving closure portion 60 on the exterior of receptacle 15. The overlap of the skirt 64 over the receptacle 15 ensures there is no direct path for radiation to escape the low-level radiation waste management system when the cover 30 is in its closed position.

The low-level radiation waste management system 10 is utilized by first placing the receptacle liner 25 in the receptacle 15, with the tie-receiving closure portion 60 everted to lie along the exterior of the receptacle. The cover is fitted over the top of the receptacle and receptacle liner. As illustrated in FIG. 1, the cover may be partially folded back or even completely opened to deposit low-level radiation wastes in the receptacle liner. Of course, the cover 30 is promptly returned to its fully closed position after the waste has been deposited. The receptacle liner 25 and cover 30 prevent the escape of radiation during storage of waste materials at the collection site. Although the interior of the receptacle liner 25 received within the receptacle and the underside of the cover 30 become contaminated by the low-level radiation waste, the everted tie-receiving closure portion 60 remains uncontaminated during this collection and containment function.

When the receptacle has been filled, or at a scheduled collection interval, the following procedure is utilized to confine and transport the low-level radiation waste. The cover is pressed into the receptacle liner, covering the wastes collected therein. Next, the everted tie-receiving closure portion 60 is pulled upwardly and gathered as shown in FIG. 2, and a tie 66 is placed about the gathered portion. It will be appreciated that some of the tie-receiving closure portion 60 is exposed above the tie 66, but that the exposed portion of the tie-receiving closure portion 60 has remained uncontaminated and does not in and of itself present any hazard. Although the gathering at the tie is generally sufficient to prevent the escape of radiation, having the cover placed over the waste below the tie is additional protection against any possible escape paths.

The tied receptacle liner, including the cover and wastes contained therein, is lifted from the receptacle 15 and may be carried or placed on a lightweight cart to remove it from the collection site. The receptacle liner may be transported to a collection site and may be buried there with the low-level radiation waste still contained therein. Of course, the receptacle liner is flexible and permits the low-level radiation wastes to be compacted as they are buried, unlike a rigid barrel system.

At the collection site, a new container set 20 is installed in the receptacle 15, and additional low-level radiation wastes are collected and contained therein.

Accordingly, the low-level radiation waste management system described above admirably achieves the objects of the invention herein. It will be appreciated, however, that the low-level radiation waste management system described is a preferred embodiment and in and of itself does not represent the full scope of the invention herein. For instance, the receptacle need not be cylindrical, and the receptacle liner and cover may be shaped appropriately for use with any receptacle shape. The location of the seams and shape of the receptacle liner may also be varied, and a more snug fit within a cylindrical receptacle could be achieved by providing the receptacle liner with a circular bottom panel, albeit at increased fabrication cost. It will further be appreciated that any flexible radiation absorbing material may be used in fabricating a container set and that the thickness of the material is selected according to its ability to block radiation and the volume of wastes to be contained therein. These and other changes departures from the preferred embodiment described above may be made by those skilled in the art without departing from the spirit and scope of the invention, which is limited only by the following claims.